after the Crusaders pulled the rug from under their feet, kicked Mohamad, kicked the native Christians in the *&&^ and ran away.
I unfortunately have to agree with this, as edited above. I hate to sound anti-Western - I'm really not - but this really is a case where (the then-resurgent) Western Europe did not produce good fruits, and the Latin Church unfortunately was highly culpable.
[“was” I say because I believe recent Popes have apologized, though the Latin Church’s awareness of how bad things got is still IMO insufficient, sometimes negatively effecting interaction and dialogue]
First, per your previous question, I call the empire in Constantinople the “Roman Empire” and the people there “Romans” because that's what they called themselves, and they are my ancestors. "Byzantine" is a name given to them in the Renaissance to further separate that empire from the Renaissance classicists' idealized ancient Rome.
Second, there is no doubt that many of the crusaders victories were significant military feats, something that requires will and morale, and in that sense are notable, and sometimes unquestionably admirable as military feats.
Third, I do not doubt the sincerity of some of the crusaders. Some of the religious orders, as much as the concept is odd for Eastern Christians, conducted themselves well, though others (in particular the Normans), were out for themselves and not for "Christendom".
However, in the end, nothing good for the Christians of the Middle East came from the crusades. During Latin rule, aside from the Maronites and some of the Armenians, they were either ignored, given second class status (compared to Latin Christianity), considered enemies or expelled. (I would note that similar happened in the Greek Islands under Venetian rule) Of course, afterwards, all Christians were considered collaborators by the Muslims.
From the perspective of Chalcedonian Eastern Christians (i.e. those in the Empire and those in union with the Empire), crusading – Papally authorized calls for troops to go fight - were an unmitigated disaster.
Politically, the Emperor asked the pope for troops to help shore up the Roman frontier (also note that anti-Norman and anti-German politics probably had some play in this). He was not expecting a mass movement of loosely-organized knights running around Anatolia, forming their own states, expelling his representatives, massacring "his" people (i.e. the Chalcedonian Christians of the Middle East), , causing excessive political headaches with the Muslims (the crusaders could always go to a home where they would not worry about Muslims. The Romans home was right next to the Muslims and had to deal with them when they got overly upset), and going on a principled but likely unsustainable attempt to conquer Jerusalem. Moreover, Crusaders would almost always kick out the local bishop, appoint their own, and massacre/expeltheir flocks, or reduce the flocks to what amounted to dhimmitude, except with the Latins replacing the Muslims on top.
Moreover, once Constantinople was taken by the rogue 4th crusade (abetted by dynastic squabbling all too typical of both pagan and Christian Roman politics), you are aware that the Pope specifically praised the unexpected act as ending the "schism" (while condemning crusader's excess) and that him and many subsequent pope specifically called for crusades against "schismatics" to prop up the Latin "Empire" in Constantinople and fight the natives.
The “Latin dhimmitdue” combined with these crusades in Greece, the Ionian islands and Anatolia are part of the reasons many Greek Christians preferred Muslim versus Latin rulers once the Empire crumbled - the experience of expulsions or functional dhimmitude under the Latins was perceived to be worse than actual dhimmitude under the Muslim.
Seems in your view, the Latin Crusaders did such a good job usurping Christianity in the East it never recovered.
The answer would be, "yes". The crusades were awful for the native Christians, some more than others, but still bad.
If you want a discussion from a Catholic source, see "History of the Melkite Patriarchates Volume 1 Pre-Modern Period", written by one of Rome's top "Orientalists" of the early 1900s and translated under the supervision of the man who is now the Melkite Catholic bishop in the US:https://secure.webvalence.com/ecommerce/kiosk.lasso?merchant=ecpubs&kiosk=books&class=6
As far as today goes, I think everyone would like some of the current Middle Eastern governments (in particular Egypt and Syria) to protect the rights of all citizens and residents regardless of creed or sect, but doing so constructively is hard. Moreover, my understanding of Middle Eastern politics is that expecting them to do so is unrealistic – oftentimes, politics is viewed as a winner-takes-all-for-his-backers-or-sect kind of affair. The West can probably work good there, but it will have to be careful and tread lightly unless something egregious (e.g. systematic persecution of Copts) takes place.
[as an aside, my stone throwing at Old Rome is one sided because it’s the topic here. There are plenty of stones that could be thrown against Constantinople as well]